Archive for the ‘Measurements’ Category
In this short post we will see how to do a measurement of resistance when you have to test a grounding system and how to do a ground resistance measurement.
**Little theoretical summary**
One of the major causes of injuries and danger in the electrical systems are high failure voltages (rated value of the system plus the power surge), due to generally high failure current (look at this post) of systems. Those currents are usually drained to ground by grounding systems. It’s easy to understand why you want the lowest resistance possible in the grounding system, merely:
RG = UG / IF (1)
Ok, let’s say you want to do a measurement of the short-circuit impedance relating to the electrical system of a house/room/lab/whatever. This is something you usually have to do if you want to choose the correct level of the protective devices.
I’ll show you how to do a measurement of:
- short-circuit impedance in case of a single-phase failure;
- short-circuit impedance in case of a two-phase failure.
All you need is an impmeter and a multimeter.